1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
4 * SPDX-License-Identifier: BSD-4-Clause
6 * Copyright (c) 2009-2016 Dmitry Chagin
7 * Copyright (c) 2005 Emmanuel Dreyfus
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by Emmanuel Dreyfus
21 * 4. The name of the author may not be used to endorse or promote
22 * products derived from this software without specific prior written
25 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
26 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
44 #include "opt_compat.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/imgact.h>
49 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/mutex.h>
56 #include <sys/queue.h>
57 #include <sys/sched.h>
61 #include <vm/vm_extern.h>
64 #include <machine/../linux32/linux.h>
65 #include <machine/../linux32/linux32_proto.h>
67 #include <machine/../linux/linux.h>
68 #include <machine/../linux/linux_proto.h>
70 #include <compat/linux/linux_dtrace.h>
71 #include <compat/linux/linux_emul.h>
72 #include <compat/linux/linux_futex.h>
73 #include <compat/linux/linux_timer.h>
74 #include <compat/linux/linux_util.h>
77 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
80 * Futex part for the special DTrace module "locks".
82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
83 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
88 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
89 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
92 * DTrace probes in this module.
94 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
95 "struct waiting_proc *");
96 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
98 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
100 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
101 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
103 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
104 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
106 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
107 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
108 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
109 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
110 "struct waiting_proc **", "struct futex **");
111 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
112 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
113 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
114 "struct waiting_proc **", "struct timespec *");
115 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
116 "struct waiting_proc *", "uint32_t *", "uint32_t");
117 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
118 "struct waiting_proc *");
119 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
120 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
122 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
123 "struct waiting_proc *", "uint32_t");
124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
125 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
126 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
127 "struct futex *", "int");
128 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
129 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
130 "struct waiting_proc *", "uint32_t");
131 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
132 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
133 "struct waiting_proc **", "struct timespec *", "uint32_t");
134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
135 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
136 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
138 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
140 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
143 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
144 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
145 "struct linux_sys_futex_args *");
146 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
147 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
148 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
149 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
150 "uint32_t", "uint32_t");
151 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
152 "uint32_t *", "uint32_t", "int", "uint32_t");
153 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
154 "uint32_t", "uint32_t");
155 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
156 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
157 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
159 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
160 "int", "uint32_t", "uint32_t *", "uint32_t");
161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
166 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
167 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
168 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
169 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
170 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
171 "struct linux_set_robust_list_args *");
172 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
173 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
174 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
175 "struct linux_get_robust_list_args *");
176 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
177 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
178 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry,
179 "struct linux_emuldata *", "uint32_t *", "unsigned int");
180 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
181 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
182 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
183 "struct linux_robust_list **", "struct linux_robust_list **",
185 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
186 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
187 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *",
188 "struct linux_emuldata *");
189 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
190 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
194 struct waiting_proc {
196 struct futex *wp_futex;
197 TAILQ_ENTRY(waiting_proc) wp_list;
202 uint32_t *f_uaddr; /* user-supplied value, for debug */
203 struct umtx_key f_key;
206 LIST_ENTRY(futex) f_list;
207 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
210 #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck)
211 #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck)
212 #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck)
213 #define FUTEX_INIT(f) do { \
214 mtx_init(&(f)->f_lck, "ftlk", NULL, \
216 LIN_SDT_PROBE1(futex, futex, create, \
219 #define FUTEX_DESTROY(f) do { \
220 LIN_SDT_PROBE1(futex, futex, destroy, \
222 mtx_destroy(&(f)->f_lck); \
224 #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED)
225 #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED)
227 #define FUTEXES_LOCK do { \
228 mtx_lock(&futex_mtx); \
229 LIN_SDT_PROBE1(locks, futex_mtx, \
230 locked, &futex_mtx); \
232 #define FUTEXES_UNLOCK do { \
233 LIN_SDT_PROBE1(locks, futex_mtx, \
234 unlock, &futex_mtx); \
235 mtx_unlock(&futex_mtx); \
238 /* flags for futex_get() */
239 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
240 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
241 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
242 #define FUTEX_SHARED 0x8 /* shared futex */
243 #define FUTEX_DONTLOCK 0x10 /* don't lock futex */
246 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
247 * of futex where thread sleep to wp_list
250 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
251 * wp_list to prevent double wakeup.
254 static void futex_put(struct futex *, struct waiting_proc *);
255 static int futex_get0(uint32_t *, struct futex **f, uint32_t);
256 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
258 static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *);
259 static int futex_wake(struct futex *, int, uint32_t);
260 static int futex_requeue(struct futex *, int, struct futex *, int);
261 static int futex_copyin_timeout(int, struct l_timespec *, int,
263 static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *,
265 static void futex_lock(struct futex *);
266 static void futex_unlock(struct futex *);
267 static int futex_atomic_op(struct thread *, int, uint32_t *);
268 static int handle_futex_death(struct linux_emuldata *, uint32_t *,
270 static int fetch_robust_entry(struct linux_robust_list **,
271 struct linux_robust_list **, unsigned int *);
274 futex_copyin_timeout(int op, struct l_timespec *luts, int clockrt,
277 struct l_timespec lts;
281 error = copyin(luts, <s, sizeof(lts));
285 error = linux_to_native_timespec(ts, <s);
290 timespecsub(ts, &kts, ts);
291 } else if (op == LINUX_FUTEX_WAIT_BITSET) {
293 timespecsub(ts, &kts, ts);
299 futex_put(struct futex *f, struct waiting_proc *wp)
301 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
304 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
305 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
306 free(wp, M_FUTEX_WP);
310 if (--f->f_refcount == 0) {
311 LIST_REMOVE(f, f_list);
316 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
317 f->f_refcount, f->f_key.shared);
318 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
319 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
320 umtx_key_release(&f->f_key);
324 LIN_SDT_PROBE0(futex, futex_put, return);
328 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
330 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
331 f->f_uaddr, f->f_refcount, f->f_key.shared);
336 LIN_SDT_PROBE0(futex, futex_put, return);
340 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
342 struct futex *f, *tmpf;
346 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
350 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
351 AUTO_SHARE : THREAD_SHARE, &key);
353 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
354 LIN_SDT_PROBE1(futex, futex_get0, return, error);
359 LIST_FOREACH(f, &futex_list, f_list) {
360 if (umtx_key_match(&f->f_key, &key)) {
362 if (FUTEX_LOCKED(tmpf))
367 if (flags & FUTEX_DONTEXISTS) {
369 umtx_key_release(&key);
371 LIN_SDT_PROBE1(futex, futex_get0, return,
377 * Increment refcount of the found futex to
378 * prevent it from deallocation before FUTEX_LOCK()
382 umtx_key_release(&key);
384 if ((flags & FUTEX_DONTLOCK) == 0)
387 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
388 f->f_refcount, f->f_key.shared);
389 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
390 uaddr, f->f_refcount, f->f_key.shared);
392 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
397 if (flags & FUTEX_DONTCREATE) {
399 umtx_key_release(&key);
400 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
401 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
403 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
409 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
410 tmpf->f_uaddr = uaddr;
412 tmpf->f_refcount = 1;
413 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
415 TAILQ_INIT(&tmpf->f_waiting_proc);
418 * Lock the new futex before an insert into the futex_list
419 * to prevent futex usage by other.
421 if ((flags & FUTEX_DONTLOCK) == 0)
426 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
429 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
431 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
432 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
435 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
440 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
445 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
447 if (flags & FUTEX_CREATE_WP) {
448 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
451 error = futex_get0(uaddr, f, flags);
453 LIN_SDT_PROBE0(futex, futex_get, error);
455 if (flags & FUTEX_CREATE_WP)
456 free(*wp, M_FUTEX_WP);
458 LIN_SDT_PROBE1(futex, futex_get, return, error);
461 if (flags & FUTEX_CREATE_WP) {
462 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
463 (*wp)->wp_futex = *f;
466 LIN_SDT_PROBE1(futex, futex_get, return, error);
471 futex_lock(struct futex *f)
474 LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d",
475 f->f_uaddr, f->f_refcount, f->f_key.shared);
476 FUTEX_ASSERT_UNLOCKED(f);
481 futex_unlock(struct futex *f)
484 LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d",
485 f->f_uaddr, f->f_refcount, f->f_key.shared);
486 FUTEX_ASSERT_LOCKED(f);
491 futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts)
494 sbintime_t sbt, prec, tmp;
498 FUTEX_ASSERT_LOCKED(f);
501 if (uts.tv_sec > INT32_MAX / 2) {
502 over = uts.tv_sec - INT32_MAX / 2;
506 if (TIMESEL(&sbt, tmp))
515 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, sbt);
516 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d",
517 f->f_uaddr, wp, sbt, f->f_refcount);
519 error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE);
520 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
521 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
524 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
525 f->f_uaddr, wp, wp->wp_futex->f_uaddr,
526 wp->wp_futex->f_refcount);
529 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
530 " %p requeued uaddr %p ref %d",
531 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
532 wp->wp_futex->f_refcount);
538 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
541 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
542 error, f->f_uaddr, wp);
547 LIN_SDT_PROBE1(futex, futex_sleep, return, error);
552 futex_wake(struct futex *f, int n, uint32_t bitset)
554 struct waiting_proc *wp, *wpt;
557 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
560 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
564 FUTEX_ASSERT_LOCKED(f);
565 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
566 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
568 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
569 f->f_uaddr, wp, f->f_refcount);
571 * Unless we find a matching bit in
572 * the bitset, continue searching.
574 if (!(wp->wp_futex->f_bitset & bitset))
577 wp->wp_flags |= FUTEX_WP_REMOVED;
578 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
579 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
585 LIN_SDT_PROBE1(futex, futex_wake, return, count);
590 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
592 struct waiting_proc *wp, *wpt;
595 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
597 FUTEX_ASSERT_LOCKED(f);
598 FUTEX_ASSERT_LOCKED(f2);
600 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
602 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
604 wp->wp_flags |= FUTEX_WP_REMOVED;
605 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
606 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
609 LIN_SDT_PROBE3(futex, futex_requeue, requeue,
610 f->f_uaddr, wp, f2->f_uaddr);
611 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
612 f->f_uaddr, wp, f2->f_uaddr);
613 wp->wp_flags |= FUTEX_WP_REQUEUED;
614 /* Move wp to wp_list of f2 futex */
615 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
616 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
619 * Thread which sleeps on wp after waking should
620 * acquire f2 lock, so increment refcount of f2 to
621 * prevent it from premature deallocation.
632 LIN_SDT_PROBE1(futex, futex_requeue, return, count);
637 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts,
642 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
645 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
649 f->f_bitset = bitset;
650 error = futex_sleep(f, wp, ts);
652 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
653 if (error == EWOULDBLOCK)
656 LIN_SDT_PROBE1(futex, futex_wait, return, error);
661 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
663 int op = (encoded_op >> 28) & 7;
664 int cmp = (encoded_op >> 24) & 15;
665 int oparg = (encoded_op << 8) >> 20;
666 int cmparg = (encoded_op << 20) >> 20;
669 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
671 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
674 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
677 /* XXX: Linux verifies access here and returns EFAULT */
678 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
682 ret = futex_xchgl(oparg, uaddr, &oldval);
685 ret = futex_addl(oparg, uaddr, &oldval);
688 ret = futex_orl(oparg, uaddr, &oldval);
691 ret = futex_andl(~oparg, uaddr, &oldval);
694 ret = futex_xorl(oparg, uaddr, &oldval);
697 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
703 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
708 case FUTEX_OP_CMP_EQ:
709 ret = (oldval == cmparg);
711 case FUTEX_OP_CMP_NE:
712 ret = (oldval != cmparg);
714 case FUTEX_OP_CMP_LT:
715 ret = (oldval < cmparg);
717 case FUTEX_OP_CMP_GE:
718 ret = (oldval >= cmparg);
720 case FUTEX_OP_CMP_LE:
721 ret = (oldval <= cmparg);
723 case FUTEX_OP_CMP_GT:
724 ret = (oldval > cmparg);
727 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
731 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
736 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
738 int clockrt, nrwake, op_ret, ret;
739 struct linux_pemuldata *pem;
740 struct waiting_proc *wp;
741 struct futex *f, *f2;
742 struct timespec uts, *ts;
746 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
748 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
750 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
752 flags = FUTEX_SHARED;
755 * Currently support for switching between CLOCK_MONOTONIC and
756 * CLOCK_REALTIME is not present. However Linux forbids the use of
757 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
758 * FUTEX_WAIT_REQUEUE_PI.
760 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
761 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
762 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
763 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
764 LIN_SDT_PROBE0(futex, linux_sys_futex,
765 unimplemented_clockswitch);
766 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
774 case LINUX_FUTEX_WAIT:
775 args->val3 = FUTEX_BITSET_MATCH_ANY;
778 case LINUX_FUTEX_WAIT_BITSET:
779 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
780 args->val, args->val3);
781 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
782 args->uaddr, args->val, args->val3);
784 if (args->timeout != NULL) {
785 error = futex_copyin_timeout(args->op, args->timeout,
788 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
790 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
798 error = futex_get(args->uaddr, &wp, &f,
799 flags | FUTEX_CREATE_WP);
801 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
805 error = copyin_nofault(args->uaddr, &val, sizeof(val));
808 error = copyin(args->uaddr, &val, sizeof(val));
811 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
813 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
815 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
818 if (val != args->val) {
819 LIN_SDT_PROBE4(futex, linux_sys_futex,
820 debug_wait_value_neq, args->uaddr, args->val, val,
822 LINUX_CTR3(sys_futex,
823 "WAIT uaddr %p val 0x%x != uval 0x%x",
824 args->uaddr, args->val, val);
827 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
829 return (EWOULDBLOCK);
832 error = futex_wait(f, wp, ts, args->val3);
835 case LINUX_FUTEX_WAKE:
836 args->val3 = FUTEX_BITSET_MATCH_ANY;
839 case LINUX_FUTEX_WAKE_BITSET:
840 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
841 args->val, args->val3);
842 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
843 args->uaddr, args->val, args->val3);
845 error = futex_get(args->uaddr, NULL, &f,
846 flags | FUTEX_DONTCREATE);
848 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
853 td->td_retval[0] = 0;
855 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
858 td->td_retval[0] = futex_wake(f, args->val, args->val3);
862 case LINUX_FUTEX_CMP_REQUEUE:
863 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
864 args->uaddr, args->val, args->val3, args->uaddr2,
866 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
867 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
868 args->uaddr, args->val, args->val3, args->uaddr2,
872 * Linux allows this, we would not, it is an incorrect
873 * usage of declared ABI, so return EINVAL.
875 if (args->uaddr == args->uaddr2) {
876 LIN_SDT_PROBE0(futex, linux_sys_futex,
877 invalid_cmp_requeue_use);
878 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
883 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
885 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
890 * To avoid deadlocks return EINVAL if second futex
891 * exists at this time.
893 * Glibc fall back to FUTEX_WAKE in case of any error
894 * returned by FUTEX_CMP_REQUEUE.
896 error = futex_get(args->uaddr2, NULL, &f2,
897 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK);
901 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
906 error = copyin_nofault(args->uaddr, &val, sizeof(val));
910 error = copyin(args->uaddr, &val, sizeof(val));
913 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
915 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
917 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
920 if (val != args->val3) {
921 LIN_SDT_PROBE2(futex, linux_sys_futex,
922 debug_cmp_requeue_value_neq, args->val, val);
923 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
928 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
932 nrwake = (int)(unsigned long)args->timeout;
933 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
938 case LINUX_FUTEX_WAKE_OP:
939 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
940 args->uaddr, args->op, args->val, args->uaddr2, args->val3);
941 LINUX_CTR5(sys_futex, "WAKE_OP "
942 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
943 args->uaddr, args->val, args->uaddr2, args->val3,
946 if (args->uaddr == args->uaddr2) {
947 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
952 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
954 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
958 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK);
962 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
969 * This function returns positive number as results and
972 save = vm_fault_disable_pagefaults();
973 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
974 vm_fault_enable_pagefaults(save);
976 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
977 args->uaddr, op_ret);
983 error = copyin(args->uaddr2, &val, sizeof(val));
986 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
990 ret = futex_wake(f, args->val, args->val3);
994 nrwake = (int)(unsigned long)args->timeout;
997 op_ret += futex_wake(f2, nrwake, args->val3);
999 op_ret += futex_wake(f, nrwake, args->val3);
1004 futex_put(f2, NULL);
1006 td->td_retval[0] = ret;
1009 case LINUX_FUTEX_LOCK_PI:
1010 /* not yet implemented */
1011 pem = pem_find(td->td_proc);
1012 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1015 "unsupported futex_pi op\n");
1016 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1017 LIN_SDT_PROBE0(futex, linux_sys_futex,
1018 unimplemented_lock_pi);
1020 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1023 case LINUX_FUTEX_UNLOCK_PI:
1024 /* not yet implemented */
1025 pem = pem_find(td->td_proc);
1026 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1029 "unsupported futex_pi op\n");
1030 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1031 LIN_SDT_PROBE0(futex, linux_sys_futex,
1032 unimplemented_unlock_pi);
1034 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1037 case LINUX_FUTEX_TRYLOCK_PI:
1038 /* not yet implemented */
1039 pem = pem_find(td->td_proc);
1040 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1043 "unsupported futex_pi op\n");
1044 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1045 LIN_SDT_PROBE0(futex, linux_sys_futex,
1046 unimplemented_trylock_pi);
1048 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1051 case LINUX_FUTEX_REQUEUE:
1053 * Glibc does not use this operation since version 2.3.3,
1054 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
1055 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
1056 * FUTEX_REQUEUE returned EINVAL.
1058 pem = pem_find(td->td_proc);
1059 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
1062 "unsupported futex_requeue op\n");
1063 pem->flags |= LINUX_XDEPR_REQUEUEOP;
1064 LIN_SDT_PROBE0(futex, linux_sys_futex,
1065 deprecated_requeue);
1068 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
1071 case LINUX_FUTEX_WAIT_REQUEUE_PI:
1072 /* not yet implemented */
1073 pem = pem_find(td->td_proc);
1074 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1077 "unsupported futex_pi op\n");
1078 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1079 LIN_SDT_PROBE0(futex, linux_sys_futex,
1080 unimplemented_wait_requeue_pi);
1082 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1085 case LINUX_FUTEX_CMP_REQUEUE_PI:
1086 /* not yet implemented */
1087 pem = pem_find(td->td_proc);
1088 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1091 "unsupported futex_pi op\n");
1092 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1093 LIN_SDT_PROBE0(futex, linux_sys_futex,
1094 unimplemented_cmp_requeue_pi);
1096 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1101 "linux_sys_futex: unknown op %d\n", args->op);
1102 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1104 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1108 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1113 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1115 struct linux_emuldata *em;
1117 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1119 if (args->len != sizeof(struct linux_robust_list_head)) {
1120 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1121 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1126 em->robust_futexes = args->head;
1128 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1133 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1135 struct linux_emuldata *em;
1136 struct linux_robust_list_head *head;
1137 l_size_t len = sizeof(struct linux_robust_list_head);
1141 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1145 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1146 head = em->robust_futexes;
1148 td2 = tdfind(args->pid, -1);
1150 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1154 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) {
1155 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1157 PROC_UNLOCK(td2->td_proc);
1162 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1164 if (priv_check(td, PRIV_CRED_SETUID) ||
1165 priv_check(td, PRIV_CRED_SETEUID) ||
1166 p_candebug(td, td2->td_proc)) {
1167 PROC_UNLOCK(td2->td_proc);
1169 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1173 head = em->robust_futexes;
1175 PROC_UNLOCK(td2->td_proc);
1178 error = copyout(&len, args->len, sizeof(l_size_t));
1180 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1182 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1186 error = copyout(&head, args->head, sizeof(head));
1188 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1192 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1197 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
1200 uint32_t uval, nval, mval;
1204 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi);
1207 error = copyin(uaddr, &uval, 4);
1209 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1210 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1213 if ((uval & FUTEX_TID_MASK) == em->em_tid) {
1214 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1215 nval = casuword32(uaddr, uval, mval);
1218 LIN_SDT_PROBE1(futex, handle_futex_death, return,
1226 if (!pi && (uval & FUTEX_WAITERS)) {
1227 error = futex_get(uaddr, NULL, &f,
1228 FUTEX_DONTCREATE | FUTEX_SHARED);
1230 LIN_SDT_PROBE1(futex, handle_futex_death,
1235 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1241 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1246 fetch_robust_entry(struct linux_robust_list **entry,
1247 struct linux_robust_list **head, unsigned int *pi)
1252 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1254 error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1256 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1257 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1261 *entry = (void *)(uentry & ~1UL);
1264 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1268 /* This walks the list of robust futexes releasing them. */
1270 release_futexes(struct thread *td, struct linux_emuldata *em)
1272 struct linux_robust_list_head *head = NULL;
1273 struct linux_robust_list *entry, *next_entry, *pending;
1274 unsigned int limit = 2048, pi, next_pi, pip;
1275 l_long futex_offset;
1278 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em);
1280 head = em->robust_futexes;
1283 LIN_SDT_PROBE0(futex, release_futexes, return);
1287 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1288 LIN_SDT_PROBE0(futex, release_futexes, return);
1292 error = copyin(&head->futex_offset, &futex_offset,
1293 sizeof(futex_offset));
1295 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1296 LIN_SDT_PROBE0(futex, release_futexes, return);
1300 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1301 LIN_SDT_PROBE0(futex, release_futexes, return);
1305 while (entry != &head->list) {
1306 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1308 if (entry != pending)
1309 if (handle_futex_death(em,
1310 (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1311 LIN_SDT_PROBE0(futex, release_futexes, return);
1315 LIN_SDT_PROBE0(futex, release_futexes, return);
1325 sched_relinquish(curthread);
1329 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1331 LIN_SDT_PROBE0(futex, release_futexes, return);